Source capture
Authors Zhan Wang, Kun Jiang, Fu-Chun Zhang, Hui-Ke Jin
arXiv / Publisher http://arxiv.org/abs/2604.08319v1
PDF https://arxiv.org/pdf/2604.08319v1
Relevance score 4.698
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Research paradigm Theoretical
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Summary

This study employs the variational Monte Carlo method to investigate superconductivity in a two-band t-J model consisting of an itinerant orbital (orbital 0) and a quasi-localized orbital (orbital 1). The key finding is the emergence of a robust orbital-selective d-wave superconducting state, which originates entirely from the itinerant orbital 0. Analysis of the superexchange energy hierarchy reveals that the quasi-localized orbital 1 competes with superconductivity by favoring the formation of local inter-orbital bound states, which act as energy defects that disrupt phase coherence. Consequently, the superconducting order parameter decreases monotonically with increasing occupation of orbital 1. Inspired by superconductivity in the nickelate La3Ni2O7, these results highlight the crucial role of multiorbital physics beyond the single-band t-J framework and identify a concrete pathway for enhancing the superconducting transition temperature: suppressing the involvement of the localized dz2 orbital.

Materials

Methods

Keywords

  • orbital selective d wave superconductivity
  • superexchange energy hierarchy
  • inter orbital bound states

Highlights

  • The superconducting order parameter decreases monotonically with increasing occupation of the localized orbital.
  • Suppressing the involvement of the localized d_z2 orbital is identified as a route to enhance T_c.

Conclusions

  • A robust orbital-selective d-wave superconducting state emerges exclusively from the itinerant orbital.
  • The quasi-localized orbital competes with superconductivity by favoring local inter-orbital bound states that disrupt phase coherence.

Main claims

  • In the two-band t-J model, robust orbital-selective d-wave superconductivity arises exclusively from the itinerant orbital-0, while the quasi-localized orbital-1 suppresses it
    • Evidence: VMC calculations show that intra-orbital pair correlation in orbital-0 dominates, and the order parameter decreases monotonically with increasing occupancy of orbital-1

Workflow

  • Model construction — d-wave superconductivity emerges exclusively from itinerant orbital
    • Materials: Two-band t-J model on square lattice
    • Methods: Variational Monte Carlo (VMC) with Gutzwiller projected wavefunctions
    • Observations: Equal-time pair-pair correlations
  • Analysis — Orbital-1 acts as competitor, suppressing SC
    • Methods: Computation of superconducting order parameter; Orbital occupancy analysis
    • Observations: Order parameter suppressed by increasing inter-orbital hopping or energy splitting